The present invention relates to the treatment of crude hydrocarbon streams and particularly to an adsorbent material that is effective to remove troublesome components often present in such streams.
In the production of oil from underground sources, after a well has been drilled to tap into the oil-bearing rock formations, it is often necessary to break up the formations to allow the oil to flow to the well bore. This is accomplished by the use of "frac fluids" which, as the name implies, have the purpose of fracturing the rock formations in which the oil is located. These frac fluids are often based on a hydrocarbon carrier liquid and contain proppants and phosphate derivatives as gelling agents to ensure that the frac fluids do not become widely dispersed in the formations but stay adjacent the well bore. The frac fluids are pumped into the well under pressure sufficient to accomplish the above purpose and are then pumped out of the well for re-processing. However such removal is not usually complete and at least a portion of the crude extracted from the well will be contaminated by the phosphate derivatives.
The frac fluids may also be contaminated by metal values which are also present in many phosphate-containing gelling agents and the removal of such metal values is desirable since they can poison catalysts used in subsequent refining components of the refinery or be deposited in the equipment used to further process the oil. The phosphate contaminants are particularly undesirable since they are often in an acidic form or a polymerized form that either lead to corrosion damage to distillation or other refining equipment in an oil refinery unless expensive stainless steel materials are used, or cause the deposition of gummy residues that interfere with the efficient operation of the refinery components.
The "sweetening" of an oil, that is the removal of sulfur-containing contaminants such as mercaptans, is carried out by an oxidation process conducted in an alkaline environment. A desirable preliminary to such a process is the removal of naphthenic acid values from the oil to be "sweetened" and a method for the accomplishment of this removal is described in U.S. Pat. No. 5,389,240. This patent teaches passing the oil through a bed of a solid solution of at least one divalent metal oxide selected from alkaline earth metal oxides, and the oxides of cobalt, iron, nickel and zinc, and aluminum oxide. One example of such a material is hydrotalcite
An adsorbent medium has now been developed that provides improved performance over the materials described in the prior art in terms of its ability to absorb metal values, phosphate derivatives and acids. These capabilities can also be provided in the form of porous shaped media suitable for incorporation in a tower adapted for continuous operation with sufficient crush strength to withstand loading and recycling operations.